The Polynesian languages are a language family spoken in geographical Polynesia and on a patchwork of "Outliers" from south central Micronesia, to small islands off the northeast of the larger islands of the Southeast Solomon Islands and sprinkled through Vanuatu. They are classified as part of the Austronesian family, belonging to the Oceanic branch of that family. Polynesians share many unique cultural traits that resulted from about 1000 years of common development, including common linguistic development, in the Tonga and Sāmoa area through most of the first millennium BC.

There are approximately forty Polynesian languages. The most prominent of these are Tahitian, Sāmoan, Tongan, Māori and Hawaiian. Because the Polynesian islands were settled relatively recently and because internal linguistic diversification only began around 2,000 years ago, their languages retain strong commonalities. There are still many cognate words across the different islands e.g. tapu, ali'i, motu, kava (Kava culture), and tapa as well as Hawaiki, the mythical homeland for some of the cultures.

All Polynesian languages show strong similarity, particularly in vocabulary. The vowels are often stable in the descendant languages, nearly always a, e, i, o and u. The legendary homeland of the Māori of New Zealand, where w is used instead of v, is called Hawaiki; in the Cook Islands, where h is replaced with the glottal stop, it is ‘Avaiki; in the Hawaiian Islands, where w is used and k is replaced with the glottal stop, the largest island of the group is named Hawai‘i; in Sāmoa, where s has not been replaced by h, v is used instead of w, and k is replaced with the glottal stop, the largest island is called Savai'i. In the Society Islands, k and ng are replaced by the glottal stop, so the name for the ancestral homeland is pronounced Havai‘i.[2]

The contemporary classification of the Polynesian languages began with certain observations by Andrew Pawley in 1966 based on shared innovations in phonology, vocabulary and grammar showing that the East Polynesian languages were more closely related to Sāmoan than they were to Tongan, calling Tongan and its nearby relative Niuean "Tongic" and Sāmoan and all other Polynesian languages of the study "Nuclear Polynesian".[5]

Previously, there had been only lexicostatistical studies [6][7] that squarely suggested a "West Polynesian" group composed of at least Tongan and Sāmoan and that an "East Polynesian" group was equally distant from both Tongan and Sāmoan. Lexicostatistics is a controversial tool that can identify points in languages from which linguistic relations can be inferred[clarify]. Since Pawley's 1966 publication, inferring the ancient relationships of the Polynesian languages has proceeded by the more diagnostic findings of studies employing the comparative method[clarify] and the proofs of shared innovations.

Pawley published another study in 1967.[8] It began the process of extracting relationships from Polynesian languages on small islands in Melanesia, the "Polynesian Outliers", whose languages Pawley was able to trace to East Futuna in the case of those farther south and perhaps to Sāmoa itself in the case of those more to the north.

Except for some minor differentiation of the East Polynesian tree, further study paused for almost twenty years until Wilson[9] published a study of Polynesian pronominal systems in 1985 suggesting that there was a special relationship between the East Polynesian languages and all other Nuclear Polynesian but for Futunic, and calling that extra-Futunic group the "Ellicean languages". Furthermore, East Polynesian was found to more likely have emerged from extra-Sāmoan Ellicean than out of Sāmoa itself, an astonishing suggestion given the long assumption of a Sāmoan homeland for the origins of East Polynesian. Wilson named this new group "Ellicean" after the pre-independence name of Tuvalu and presented fine-grained evidence for subgroups within that overarching category.

Marck,[10] in 2000, was able to offer some support for some aspects of Wilson's suggestion through comparisons of shared sporadic (irregular, unexpected) sound changes, e. g., Proto-Polynesian and Proto-Nuclear-Polynesian *mafu 'to heal' becoming Proto-Ellicean *mafo. This was made possible by the massive Polynesian language comparative lexicon ("Pollex" - with reconstructions) of Biggs and Clark.[11]

Despite the relative low number of Polynesian languages, and the relative abundance of data already available on many of them, the comparative method was often reduced to comparisons of vocabulary, shared sporadic sound changes and, as Wilson had done in 1985, comparison of pronominal systems, which is perhaps the second most commonly described aspect of "minor" languages often available for comparison after the lexicostatistical lists. Wilson has a forthcoming work[12] providing further evidence of fine grained subgroups within Ellicean and a consideration of other recent work[13] on the matter of Ellicean internal relations. Wilson's new work brings the matter to the approximate limits of current data available, incorporating much data unknown to most other researchers.

Returning to lexicostatistics, it must be emphasised that the method does not make the best possible use of its short word lists of 100 or 200 words. Dyen's[14] massive lexicostatistical study of Austronesian, for instance, showed a great deal of (lexicostatistical) diversity in the Austronesian languages of Western Melanesia. This was sometimes on par with the lexicostatistical distance of Taiwan Austronesian languages from other Austronesian including Taiwan Austronesian languages from each other (Taiwan now definitively known to be the homeland of the language family itself). But the low lexicostatistical agreement of many Western Melanesian Oceanic languages with other Oceanic Austronesian can be easily dismissed as of little subgrouping interest because those languages are nevertheless full of diagnostic innovations of Oceanic Austronesian in their sound systems and vocabulary, including many Oceanic lexical innovations found in the 100 and 200 lexicostatistical word lists (and the deadly conclusive evidence of the shared phonological innovations of those low-scoring groups with all other Oceanic Austronesian). The Western Oceanic Melanesian "diversity" of lexicostatistical studies was never of any interest in terms of attributing any special time depth or subgrouping significance to it. They are just languages with accelerated loss of vocabulary, sometimes, in the Westerm Oceanic case, because they involve certain more ancient peoples of the region shifting to Oceanic speech after Oceanic-speaking peoples arrived.[15]

Certain regular correspondences can be noted between different Polynesian languages. For example, the Māori sounds /k/, /ɾ/, /t/, and /ŋ/ correspond to /ʔ/, /l/, /k/, and /n/ in Hawaiian. Accordingly, "man" is tangata in Māori and kanaka in Hawaiian, and Māori roa "long" corresponds to Hawaiian loa. The famous Hawaiian greeting aloha corresponds to Māori aroha, "love, tender emotion". Similarly, the Hawaiian word for kava is ʻawa.

Similarities in basic vocabulary may allow speakers from different island groups to achieve a surprising degree of understanding of each other's speech. When a particular language shows unexpectedly large divergence in vocabulary, this may be the result of a name-avoidance taboo situation – see examples in Tahitian, where this has happened often.

Many Polynesian languages have been greatly affected by European colonization. Both Māori and Hawaiian, for example, have lost much ground to English, and only in the last twenty years have they made progress towards restoration.

In general, Polynesian languages have three numbers for pronouns and possessives: singular, dual and plural. For example in Māori: ia (he/she), rāua (they two), rātou (they 3 or more). The words rua (2) and toru (3) are still discernible in endings of the dual and plural pronouns, giving the impression that the plural was originally a trial (threesome) or paucal (a few), and that an original plural has disappeared.[16] Polynesian languages have four distinctions in pronouns and possessives: first exclusive, first inclusive, second and third. For example in Māori, the plural pronouns are: mātou (we, exc), tātou (we, inc), koutou (you), rātou (they). The difference between exclusive and inclusive is the treatment of the person addressed. Mātou refers to the speaker and others but not the person or persons spoken to (i.e., "I and some others, but not you"), while tātou refers to the speaker, the person or persons spoken to, and everyone else (i.e., "You and I and others").

Many Polynesian languages distinguish two possessives. The a-possessives (as they contain that letter in most cases), also known as subjective possessives, refer to possessions that must be acquired by one's own action (alienable possession). The o-possessives or objective possessives refer to possessions that are fixed to you, unchangeable, and do not necessitate any action on your part (but upon which actions can still be performed by others) (inalienable possession). Some words can take either form, often with a difference in meaning. One example is the Sāmoan word susu, which takes the o-possessive in lona susu (her breast) and the a-possessive in lana susu (her breastmilk). Compare also the particles used in the names of two of the books of the Māori Bible: Te Pukapuka a Heremaia (The Book of Jeremiah) with Te Pukapuka o Hōhua (The Book of Joshua); the former belongs to Jeremiah in the sense that he was the author, while the Book of Joshua was written by someone else about Joshua. The distinction between one's birth village and one's current residence village can be made similarly.

Most Polynesian languages have five vowel qualities, corresponding roughly to those written i, e, a, o, u in classical Latin. Influenced by the traditions of orthographies of languages they were familiar with, the missionaries who first developed orthographies for unwritten Polynesian languages did not explicitly mark phonemic vowel length or the glottal stop. By the time that linguists trained in more modern methods made their way to the Pacific, at least for the major languages, the Bible was already printed according to the orthographic system developed by the missionaries, and the people had learned to read and write without marking vowel length or the glottal stop.

This situation persists in many languages. Despite the efforts of local academies at reform, the general conservative resistance to orthographic change has led to varying results in the languages, and several writing systems co-exist. The most common method, however, is the one where a macron is used to indicate a long vowel, while a vowel without that accent is short, for example, ā versus a. Sometimes, a long vowel is written double, e.g. Maaori. The glottal stop (not present in all Polynesian languages, but which where present is one of the most common consonants) is indicated by an apostrophe, for example, 'a versus a. This is somewhat of an anomaly as the apostrophe is most often used to represent letters that have been omitted, while the glottal stop is rather a consonant that is not written. The problem can somewhat be alleviated by changing the simple apostrophe for a curly one, taking a normal apostrophe for the elision and the inverted comma for the glottal stop. The latter method has come into common use in Polynesian languages.

^Indeed Fijian, a language closely related to Polynesian, has singular, dual, paucal, and plural; and even there we may see the paucal replacing the plural in generations to come, as the paucal currently can be used for a group from 3 up to as many as 10, usually with some family, workgroup or other association.